drivers/staging/greybus/connection.c

   1 /*
   2  * Greybus connections
   3  *
   4  * Copyright 2014 Google Inc.
   5  * Copyright 2014 Linaro Ltd.
   6  *
   7  * Released under the GPLv2 only.
   8  */
   9
  10 #include <linux/workqueue.h>
  11
  12 #include "greybus.h"
  13
  14
  15 static int gb_connection_bind_protocol(struct gb_connection *connection);
  16 static void gb_connection_unbind_protocol(struct gb_connection *connection);
  17
  18
  19 static DEFINE_SPINLOCK(gb_connections_lock);
  20
  21 /* This is only used at initialization time; no locking is required. */
  22 static struct gb_connection *
  23 gb_connection_intf_find(struct gb_interface *intf, u16 cport_id)
  24 {
  25         struct gb_host_device *hd = intf->hd;
  26         struct gb_connection *connection;
  27
  28         list_for_each_entry(connection, &hd->connections, hd_links) {
  29                 if (connection->intf == intf &&
  30                                 connection->intf_cport_id == cport_id)
  31                         return connection;
  32         }
  33
  34         return NULL;
  35 }
  36
  37 static struct gb_connection *
  38 gb_connection_hd_find(struct gb_host_device *hd, u16 cport_id)
  39 {
  40         struct gb_connection *connection;
  41         unsigned long flags;
  42
  43         spin_lock_irqsave(&gb_connections_lock, flags);
  44         list_for_each_entry(connection, &hd->connections, hd_links)
  45                 if (connection->hd_cport_id == cport_id)
  46                         goto found;
  47         connection = NULL;
  48 found:
  49         spin_unlock_irqrestore(&gb_connections_lock, flags);
  50
  51         return connection;
  52 }
  53
  54 /*
  55  * Callback from the host driver to let us know that data has been
  56  * received on the bundle.
  57  */
  58 void greybus_data_rcvd(struct gb_host_device *hd, u16 cport_id,
  59                         u8 *data, size_t length)
  60 {
  61         struct gb_connection *connection;
  62
  63         connection = gb_connection_hd_find(hd, cport_id);
  64         if (!connection) {
  65                 dev_err(&hd->dev,
  66                         "nonexistent connection (%zu bytes dropped)\n", length);
  67                 return;
  68         }
  69         gb_connection_recv(connection, data, length);
  70 }
  71 EXPORT_SYMBOL_GPL(greybus_data_rcvd);
  72
  73 static DEFINE_MUTEX(connection_mutex);
  74
  75 static void gb_connection_kref_release(struct kref *kref)
  76 {
  77         struct gb_connection *connection;
  78
  79         connection = container_of(kref, struct gb_connection, kref);
  80         destroy_workqueue(connection->wq);
  81         kfree(connection);
  82         mutex_unlock(&connection_mutex);
  83 }
  84
  85 static void gb_connection_init_name(struct gb_connection *connection)
  86 {
  87         u16 hd_cport_id = connection->hd_cport_id;
  88         u16 cport_id = 0;
  89         u8 intf_id = 0;
  90
  91         if (connection->intf) {
  92                 intf_id = connection->intf->interface_id;
  93                 cport_id = connection->intf_cport_id;
  94         }
  95
  96         snprintf(connection->name, sizeof(connection->name),
  97                         "%u/%u:%u", hd_cport_id, intf_id, cport_id);
  98 }
  99
 100 /*
 101  * gb_connection_create() - create a Greybus connection
 102  * @hd:                 host device of the connection
 103  * @hd_cport_id:        host-device cport id, or -1 for dynamic allocation
 104  * @intf:               remote interface, or NULL for static connections
 105  * @bundle:             remote-interface bundle (may be NULL)
 106  * @cport_id:           remote-interface cport id, or 0 for static connections
 107  * @protocol_id:        protocol id
 108  *
 109  * Create a Greybus connection, representing the bidirectional link
 110  * between a CPort on a (local) Greybus host device and a CPort on
 111  * another Greybus interface.
 112  *
 113  * A connection also maintains the state of operations sent over the
 114  * connection.
 115  *
 116  * Return: A pointer to the new connection if successful, or NULL otherwise.
 117  */
 118 static struct gb_connection *
 119 gb_connection_create(struct gb_host_device *hd, int hd_cport_id,
 120                                 struct gb_interface *intf,
 121                                 struct gb_bundle *bundle, int cport_id,
 122                                 u8 protocol_id)
 123 {
 124         struct gb_connection *connection;
 125         struct ida *id_map = &hd->cport_id_map;
 126         int ida_start, ida_end;
 127         u8 major = 0;
 128         u8 minor = 1;
 129
 130         /*
 131          * If a manifest tries to reuse a cport, reject it.  We
 132          * initialize connections serially so we don't need to worry
 133          * about holding the connection lock.
 134          */
 135         if (bundle && gb_connection_intf_find(bundle->intf, cport_id)) {
 136                 dev_err(&bundle->dev, "cport %u already connected\n",
 137                                 cport_id);
 138                 return NULL;
 139         }
 140
 141         if (hd_cport_id < 0) {
 142                 ida_start = 0;
 143                 ida_end = hd->num_cports;
 144         } else if (hd_cport_id < hd->num_cports) {
 145                 ida_start = hd_cport_id;
 146                 ida_end = hd_cport_id + 1;
 147         } else {
 148                 dev_err(&hd->dev, "cport %d not available\n", hd_cport_id);
 149                 return NULL;
 150         }
 151
 152         hd_cport_id = ida_simple_get(id_map, ida_start, ida_end, GFP_KERNEL);
 153         if (hd_cport_id < 0)
 154                 return NULL;
 155
 156         connection = kzalloc(sizeof(*connection), GFP_KERNEL);
 157         if (!connection)
 158                 goto err_remove_ida;
 159
 160         connection->hd_cport_id = hd_cport_id;
 161         connection->intf_cport_id = cport_id;
 162         connection->hd = hd;
 163         connection->intf = intf;
 164
 165         connection->protocol_id = protocol_id;
 166         connection->major = major;
 167         connection->minor = minor;
 168
 169         connection->bundle = bundle;
 170         connection->state = GB_CONNECTION_STATE_DISABLED;
 171
 172         atomic_set(&connection->op_cycle, 0);
 173         mutex_init(&connection->mutex);
 174         spin_lock_init(&connection->lock);
 175         INIT_LIST_HEAD(&connection->operations);
 176
 177         connection->wq = alloc_workqueue("%s:%d", WQ_UNBOUND, 1,
 178                                          dev_name(&hd->dev), hd_cport_id);
 179         if (!connection->wq)
 180                 goto err_free_connection;
 181
 182         kref_init(&connection->kref);
 183
 184         gb_connection_init_name(connection);
 185
 186         spin_lock_irq(&gb_connections_lock);
 187         list_add(&connection->hd_links, &hd->connections);
 188
 189         if (bundle)
 190                 list_add(&connection->bundle_links, &bundle->connections);
 191         else
 192                 INIT_LIST_HEAD(&connection->bundle_links);
 193
 194         spin_unlock_irq(&gb_connections_lock);
 195
 196         return connection;
 197
 198 err_free_connection:
 199         kfree(connection);
 200 err_remove_ida:
 201         ida_simple_remove(id_map, hd_cport_id);
 202
 203         return NULL;
 204 }
 205
 206 struct gb_connection *
 207 gb_connection_create_static(struct gb_host_device *hd,
 208                                         u16 hd_cport_id, u8 protocol_id)
 209 {
 210         return gb_connection_create(hd, hd_cport_id, NULL, NULL, 0,
 211                                                                 protocol_id);
 212 }
 213
 214 struct gb_connection *
 215 gb_connection_create_dynamic(struct gb_interface *intf,
 216                                         struct gb_bundle *bundle,
 217                                         u16 cport_id, u8 protocol_id)
 218 {
 219         return gb_connection_create(intf->hd, -1, intf, bundle, cport_id,
 220                                                                 protocol_id);
 221 }
 222
 223 static int gb_connection_hd_cport_enable(struct gb_connection *connection)
 224 {
 225         struct gb_host_device *hd = connection->hd;
 226         int ret;
 227
 228         if (!hd->driver->cport_enable)
 229                 return 0;
 230
 231         ret = hd->driver->cport_enable(hd, connection->hd_cport_id);
 232         if (ret) {
 233                 dev_err(&hd->dev,
 234                         "failed to enable host cport: %d\n", ret);
 235                 return ret;
 236         }
 237
 238         return 0;
 239 }
 240
 241 static void gb_connection_hd_cport_disable(struct gb_connection *connection)
 242 {
 243         struct gb_host_device *hd = connection->hd;
 244
 245         if (!hd->driver->cport_disable)
 246                 return;
 247
 248         hd->driver->cport_disable(hd, connection->hd_cport_id);
 249 }
 250
 251 /*
 252  * Request the SVC to create a connection from AP's cport to interface's
 253  * cport.
 254  */
 255 static int
 256 gb_connection_svc_connection_create(struct gb_connection *connection)
 257 {
 258         struct gb_host_device *hd = connection->hd;
 259         struct gb_interface *intf;
 260         int ret;
 261
 262         if (gb_connection_is_static(connection))
 263                 return 0;
 264
 265         intf = connection->intf;
 266         ret = gb_svc_connection_create(hd->svc,
 267                         hd->svc->ap_intf_id,
 268                         connection->hd_cport_id,
 269                         intf->interface_id,
 270                         connection->intf_cport_id,
 271                         intf->boot_over_unipro);
 272         if (ret) {
 273                 dev_err(&connection->hd->dev,
 274                         "%s: failed to create svc connection: %d\n",
 275                         connection->name, ret);
 276                 return ret;
 277         }
 278
 279         return 0;
 280 }
 281
 282 static void
 283 gb_connection_svc_connection_destroy(struct gb_connection *connection)
 284 {
 285         if (gb_connection_is_static(connection))
 286                 return;
 287
 288         gb_svc_connection_destroy(connection->hd->svc,
 289                                   connection->hd->svc->ap_intf_id,
 290                                   connection->hd_cport_id,
 291                                   connection->intf->interface_id,
 292                                   connection->intf_cport_id);
 293 }
 294
 295 /* Inform Interface about active CPorts */
 296 static int gb_connection_control_connected(struct gb_connection *connection)
 297 {
 298         struct gb_control *control;
 299         u16 cport_id = connection->intf_cport_id;
 300         int ret;
 301
 302         if (gb_connection_is_static(connection))
 303                 return 0;
 304
 305         control = connection->intf->control;
 306
 307         if (connection == control->connection)
 308                 return 0;
 309
 310         ret = gb_control_connected_operation(control, cport_id);
 311         if (ret) {
 312                 dev_err(&connection->bundle->dev,
 313                         "failed to connect cport: %d\n", ret);
 314                 return ret;
 315         }
 316
 317         return 0;
 318 }
 319
 320 /* Inform Interface about inactive CPorts */
 321 static void
 322 gb_connection_control_disconnected(struct gb_connection *connection)
 323 {
 324         struct gb_control *control;
 325         u16 cport_id = connection->intf_cport_id;
 326         int ret;
 327
 328         if (gb_connection_is_static(connection))
 329                 return;
 330
 331         control = connection->intf->control;
 332
 333         if (connection == control->connection)
 334                 return;
 335
 336         ret = gb_control_disconnected_operation(control, cport_id);
 337         if (ret) {
 338                 dev_warn(&connection->bundle->dev,
 339                          "failed to disconnect cport: %d\n", ret);
 340         }
 341 }
 342
 343 /*
 344  * Request protocol version supported by the module.
 345  */
 346 static int gb_connection_protocol_get_version(struct gb_connection *connection)
 347 {
 348         int ret;
 349
 350         ret = gb_protocol_get_version(connection);
 351         if (ret) {
 352                 dev_err(&connection->hd->dev,
 353                         "%s: failed to get protocol version: %d\n",
 354                         connection->name, ret);
 355                 return ret;
 356         }
 357
 358         return 0;
 359 }
 360
 361 /*
 362  * Cancel all active operations on a connection.
 363  *
 364  * Locking: Called with connection lock held and state set to DISABLED.
 365  */
 366 static void gb_connection_cancel_operations(struct gb_connection *connection,
 367                                                 int errno)
 368 {
 369         struct gb_operation *operation;
 370
 371         while (!list_empty(&connection->operations)) {
 372                 operation = list_last_entry(&connection->operations,
 373                                                 struct gb_operation, links);
 374                 gb_operation_get(operation);
 375                 spin_unlock_irq(&connection->lock);
 376
 377                 if (gb_operation_is_incoming(operation))
 378                         gb_operation_cancel_incoming(operation, errno);
 379                 else
 380                         gb_operation_cancel(operation, errno);
 381
 382                 gb_operation_put(operation);
 383
 384                 spin_lock_irq(&connection->lock);
 385         }
 386 }
 387
 388 /*
 389  * Cancel all active incoming operations on a connection.
 390  *
 391  * Locking: Called with connection lock held and state set to ENABLED_TX.
 392  */
 393 static void
 394 gb_connection_flush_incoming_operations(struct gb_connection *connection,
 395                                                 int errno)
 396 {
 397         struct gb_operation *operation;
 398         bool incoming;
 399
 400         while (!list_empty(&connection->operations)) {
 401                 incoming = false;
 402                 list_for_each_entry(operation, &connection->operations,
 403                                                                 links) {
 404                         if (gb_operation_is_incoming(operation)) {
 405                                 gb_operation_get(operation);
 406                                 incoming = true;
 407                                 break;
 408                         }
 409                 }
 410
 411                 if (!incoming)
 412                         break;
 413
 414                 spin_unlock_irq(&connection->lock);
 415
 416                 /* FIXME: flush, not cancel? */
 417                 gb_operation_cancel_incoming(operation, errno);
 418                 gb_operation_put(operation);
 419
 420                 spin_lock_irq(&connection->lock);
 421         }
 422 }
 423
 424 int gb_connection_enable(struct gb_connection *connection,
 425                                 gb_request_handler_t handler)
 426 {
 427         int ret;
 428
 429         mutex_lock(&connection->mutex);
 430
 431         if (connection->state == GB_CONNECTION_STATE_ENABLED)
 432                 goto out_unlock;
 433
 434         if (connection->state == GB_CONNECTION_STATE_ENABLED_TX) {
 435                 if (!handler)
 436                         goto out_unlock;
 437
 438                 spin_lock_irq(&connection->lock);
 439                 connection->handler = handler;
 440                 connection->state = GB_CONNECTION_STATE_ENABLED;
 441                 spin_unlock_irq(&connection->lock);
 442
 443                 goto out_unlock;
 444         }
 445
 446         ret = gb_connection_hd_cport_enable(connection);
 447         if (ret)
 448                 goto err_unlock;
 449
 450         ret = gb_connection_svc_connection_create(connection);
 451         if (ret)
 452                 goto err_hd_cport_disable;
 453
 454         spin_lock_irq(&connection->lock);
 455         connection->handler = handler;
 456         if (handler)
 457                 connection->state = GB_CONNECTION_STATE_ENABLED;
 458         else
 459                 connection->state = GB_CONNECTION_STATE_ENABLED_TX;
 460         spin_unlock_irq(&connection->lock);
 461
 462         ret = gb_connection_control_connected(connection);
 463         if (ret)
 464                 goto err_svc_destroy;
 465
 466 out_unlock:
 467         mutex_unlock(&connection->mutex);
 468
 469         return 0;
 470
 471 err_svc_destroy:
 472         spin_lock_irq(&connection->lock);
 473         connection->state = GB_CONNECTION_STATE_DISABLED;
 474         gb_connection_cancel_operations(connection, -ESHUTDOWN);
 475         connection->handler = NULL;
 476         spin_unlock_irq(&connection->lock);
 477
 478         gb_connection_svc_connection_destroy(connection);
 479 err_hd_cport_disable:
 480         gb_connection_hd_cport_disable(connection);
 481 err_unlock:
 482         mutex_unlock(&connection->mutex);
 483
 484         return ret;
 485 }
 486 EXPORT_SYMBOL_GPL(gb_connection_enable);
 487
 488 void gb_connection_disable_rx(struct gb_connection *connection)
 489 {
 490         mutex_lock(&connection->mutex);
 491
 492         spin_lock_irq(&connection->lock);
 493         if (connection->state != GB_CONNECTION_STATE_ENABLED) {
 494                 spin_unlock_irq(&connection->lock);
 495                 goto out_unlock;
 496         }
 497         connection->state = GB_CONNECTION_STATE_ENABLED_TX;
 498         gb_connection_flush_incoming_operations(connection, -ESHUTDOWN);
 499         connection->handler = NULL;
 500         spin_unlock_irq(&connection->lock);
 501
 502 out_unlock:
 503         mutex_unlock(&connection->mutex);
 504 }
 505
 506 void gb_connection_disable(struct gb_connection *connection)
 507 {
 508         mutex_lock(&connection->mutex);
 509
 510         if (connection->state == GB_CONNECTION_STATE_DISABLED)
 511                 goto out_unlock;
 512
 513         gb_connection_control_disconnected(connection);
 514
 515         spin_lock_irq(&connection->lock);
 516         connection->state = GB_CONNECTION_STATE_DISABLED;
 517         gb_connection_cancel_operations(connection, -ESHUTDOWN);
 518         connection->handler = NULL;
 519         spin_unlock_irq(&connection->lock);
 520
 521         gb_connection_svc_connection_destroy(connection);
 522         gb_connection_hd_cport_disable(connection);
 523
 524 out_unlock:
 525         mutex_unlock(&connection->mutex);
 526 }
 527 EXPORT_SYMBOL_GPL(gb_connection_disable);
 528
 529 static int gb_legacy_request_handler(struct gb_operation *operation)
 530 {
 531         struct gb_protocol *protocol = operation->connection->protocol;
 532
 533         return protocol->request_recv(operation->type, operation);
 534 }
 535
 536 int gb_connection_legacy_init(struct gb_connection *connection)
 537 {
 538         gb_request_handler_t handler;
 539         int ret;
 540
 541         ret = gb_connection_bind_protocol(connection);
 542         if (ret)
 543                 return ret;
 544
 545         if (connection->protocol->request_recv)
 546                 handler = gb_legacy_request_handler;
 547         else
 548                 handler = NULL;
 549
 550         ret = gb_connection_enable(connection, handler);
 551         if (ret)
 552                 goto err_unbind_protocol;
 553
 554         ret = gb_connection_protocol_get_version(connection);
 555         if (ret)
 556                 goto err_disable;
 557
 558         ret = connection->protocol->connection_init(connection);
 559         if (ret)
 560                 goto err_disable;
 561
 562         return 0;
 563
 564 err_disable:
 565         gb_connection_disable(connection);
 566 err_unbind_protocol:
 567         gb_connection_unbind_protocol(connection);
 568
 569         return ret;
 570 }
 571 EXPORT_SYMBOL_GPL(gb_connection_legacy_init);
 572
 573 void gb_connection_legacy_exit(struct gb_connection *connection)
 574 {
 575         if (connection->state == GB_CONNECTION_STATE_DISABLED)
 576                 return;
 577
 578         gb_connection_disable(connection);
 579
 580         connection->protocol->connection_exit(connection);
 581
 582         gb_connection_unbind_protocol(connection);
 583 }
 584 EXPORT_SYMBOL_GPL(gb_connection_legacy_exit);
 585
 586 /*
 587  * Tear down a previously set up connection.
 588  */
 589 void gb_connection_destroy(struct gb_connection *connection)
 590 {
 591         struct ida *id_map;
 592
 593         if (WARN_ON(!connection))
 594                 return;
 595
 596         spin_lock_irq(&gb_connections_lock);
 597         list_del(&connection->bundle_links);
 598         list_del(&connection->hd_links);
 599         spin_unlock_irq(&gb_connections_lock);
 600
 601         id_map = &connection->hd->cport_id_map;
 602         ida_simple_remove(id_map, connection->hd_cport_id);
 603         connection->hd_cport_id = CPORT_ID_BAD;
 604
 605         kref_put_mutex(&connection->kref, gb_connection_kref_release,
 606                        &connection_mutex);
 607 }
 608
 609 void gb_connection_latency_tag_enable(struct gb_connection *connection)
 610 {
 611         struct gb_host_device *hd = connection->hd;
 612         int ret;
 613
 614         if (!hd->driver->latency_tag_enable)
 615                 return;
 616
 617         ret = hd->driver->latency_tag_enable(hd, connection->hd_cport_id);
 618         if (ret) {
 619                 dev_err(&connection->hd->dev,
 620                         "%s: failed to enable latency tag: %d\n",
 621                         connection->name, ret);
 622         }
 623 }
 624 EXPORT_SYMBOL_GPL(gb_connection_latency_tag_enable);
 625
 626 void gb_connection_latency_tag_disable(struct gb_connection *connection)
 627 {
 628         struct gb_host_device *hd = connection->hd;
 629         int ret;
 630
 631         if (!hd->driver->latency_tag_disable)
 632                 return;
 633
 634         ret = hd->driver->latency_tag_disable(hd, connection->hd_cport_id);
 635         if (ret) {
 636                 dev_err(&connection->hd->dev,
 637                         "%s: failed to disable latency tag: %d\n",
 638                         connection->name, ret);
 639         }
 640 }
 641 EXPORT_SYMBOL_GPL(gb_connection_latency_tag_disable);
 642
 643 static int gb_connection_bind_protocol(struct gb_connection *connection)
 644 {
 645         struct gb_protocol *protocol;
 646
 647         protocol = gb_protocol_get(connection->protocol_id,
 648                                    connection->major,
 649                                    connection->minor);
 650         if (!protocol) {
 651                 dev_err(&connection->hd->dev,
 652                                 "protocol 0x%02x version %u.%u not found\n",
 653                                 connection->protocol_id,
 654                                 connection->major, connection->minor);
 655                 return -EPROTONOSUPPORT;
 656         }
 657         connection->protocol = protocol;
 658
 659         return 0;
 660 }
 661
 662 static void gb_connection_unbind_protocol(struct gb_connection *connection)
 663 {
 664         struct gb_protocol *protocol = connection->protocol;
 665
 666         gb_protocol_put(protocol);
 667
 668         connection->protocol = NULL;
 669 }